Rapid-Fluorescence-in-Situ-Hybridization (FISH) on Uncultured Amniocytes for Avoiding Birth Defects due to Common Chromosomal Aberrations

Abstract

Background Birth defects are structural or functional abnormalities present at birth that can cause physical or mental disability in new borns. Birth defects can be due to genetic problems caused by mutation in one or more genes, chromosome aneuploidy or environmental factors in women exposed during pregnancy. Objective The aim of the study was to evaluate the effectiveness of the Rapid-Fluorescence-in-Situ-Hybridization (Rapid-FISH) technique in detecting numerical chromosome aberrations of 13, 21, 18, X and Y in amniocyte nuclei from amniotic fluid for avoiding birth defects due to chromosome abnormalities performed on 138 high risk pregnancies. Methods The FISH was performed using AneuVysion kit (Vysis, Inc), according to a standard protocol. Results A total of one hundred thirty eight samples were received for full karyotype and FISH. The average age of mothers and their gestational ages were 33 years and 17.5 weeks respectively. Triple test screening was positive in 52.9% of the women followed by advanced maternal age and ultrasonographic abnormalities. Interphase FISH was performed on seventy eight specimens. All normal and abnormal results were confirmed by classical cytogenetic method (GTG banding and karyotyping). The overall detection rate for aneuploidies through FISH was 100%. Aneuploidy was identified in 5 out of 78 specimens (four cases of trisomy 21 and one case of Turner syndrome) taken for FISH. It was concluded that Rapid-FISH is a reliable and fast method for detecting numerical chromosomal aberrations through prenatal diagnosis and has been implemented as a routine diagnostic procedure in pregnancies with high risk of fetal aneuploidy for avoiding chromosomes 13, 18, 21, X, Y related birth defects.